1. Field of the Invention
This invention relates to an iontophoresis-based medical device for sterilizing and disinfecting body tissues and, more particularly, to an iontophoresis-based medical device for sterilizing and disinfecting body tissues to treat a part of an animal affected by a pathogen, for example, by using a drug solution permeated into the lesion by means of iontophoresis.
2. Description of the Prior Art
A conventional iontophoresis-based medical device for sterilizing and treating a tooth infected with a pathogenic organism by iontophoresis is known, for example, as the device claimed in the Patent literature 1.
The conventional iontophoresis-based medical device was provided with an electric circuit having a voltage generator and a current-supplied application apparatus, a positive electrode section and a negative electrode section, wherein the positive electrode section was provided needle-shaped and deeply inserted into a tooth duct and the negative electrode section was directly attached to a part of a patient body, and the voltage generator fed a direct current and the electric circuit was provided with an apparatus to maintain a constant direct current while an impedance of the electric circuit varied, and the impedance was determined depending on a body part of a patient through which a current passed.
In sterilizing and treating a tooth, a drug solution applied to the needle-shaped positive electrode section was inserted into a tooth duct, and the negative electrode section was attached to a part of a patient (for example, the wrist) to effect electric conduction. This process made it possible to provide a closed electric circuit among the power source, the electric circuit, the positive and negative electrode sections, the tooth and the part of the patient, thereby allowing permeation of the drug solution deeply into the tooth duct by iontophoresis to sterilize and treat the lesion.
[Patent literature 1] Japanese Published Unexamined Patent Application No. 2001-293016 (FIG. 1 on page 1)
Drug solutions including halogen elements such as fluorine, iodine or chloride were used as those permeated into a lesion in treatment by conventional iontophoresis-based medical devices. Drug solutions including metal elements such as silver or zinc were also used.
However, as described above, the conventional iontophoresis-based medical device was provided with a needle-shaped positive electrode section directly contacting with a lesion. Such a shape of the positive electrode section provided a lesion with a limited quantity of a drug solution at one time. Therefore, in order to attain a predetermined therapeutic effect, it was necessary to discontinue treatment to apply the drug solution to the positive electrode section several times, thus resulting in a prolonged treatment.
Further, according to the conventional iontophoresis-based medical device, the negative electrode section was designed to be attached to apart of the body largely apart from the lesion, for example, the wrist. Thus, the negative electrode section was a great distance from the positive electrode section and unable to give a sufficient iontophoresis-based therapeutic effect to the lesion.
In addition, the negative electrode section was required to have a dimension sufficient to be worn on the wrist. Further, in order to detachably attach the negative electrode section to the wrist conveniently, such an attachable and detachable structure as a spring-mounted supporting structure or belt-fastening structure was needed, entailing troublesome wearing and removing processes. Consequently, it was difficult to handle these electrode sections at the time of treatment.
In addition, conventional drug solutions were restricted to either drug solutions containing halogen elements or those containing metallic elements. Iontophoresis methods using these drug solutions were low in sterilization effect and none of them were able to attain a sufficient sterilization and treatment.